The invention relates to an apparatus for palletizing unit loads for forming a stack of unit loads and including a unit load feeder, an intermittent conveyor for separating the unit loads, and an input roller conveyor having a plurality of driven rollers and a waiting area, with the unit load feeder, the intermittent conveyor and the input roller conveyor being displaceable in the same direction. A guide is displaceable between rollers of the input roller conveyor for displacing the unit loads from a driven roller region to the waiting area. The guide comprises a plurality of guide elements adapted to be lifted above and sank beneath an upper surface level of the rollers of the input roller conveyor. The apparatus also includes a stacker for forming stacks of the unit loads and located adjacent to and sidewise of the input roller conveyor, and sliding means for shifting a unit load layer formed in the waiting area of the input roller conveyor onto the stacker.
The invention also recites a method of palletizing unit loads effecting with the above-described palletizing apparatus and including feeding the unit loads with the unit load feeder to the intermittent conveyor, separating the unit loads fed to the intermittent conveyor into groups of a predetermined number of unit loads on the intermittent conveyor and, thereafter, feeding the predetermined number of unit loads from the intermittent conveyor to the input roller conveyor. The method further includes forming the predetermined number of unit loads fed to the input roller conveyor into rows of unit loads, lifting a first row of unit loads with the stirrup-shaped elements of the guide above the upper surface level of the input roller conveyor and displacing the first row sidewise into the waiting area, returning the guide to its initial position, and, thereafter, lifting a second row of unit loads with stirrup-shaped elements above the upper surface level of the input roller conveyor and displacing the guide with the second row into the waiting area. The method also includes displacing the unit load layer formed of the first and second rows onto the stacker.
The above-described apparatus and method are generally known (please see, e.g., a prospectus of the assignee of the present application "Bag Palletizing Apparatus"). The known apparatus and method permits the forming of layers of unit loads arranged according to a predetermined pattern, with some of the unit loads being pivoted by 90.degree. before their separation into groups of unit loads. A group can consist of single unit loads spaced from each other, or of sets of two or three unit loads abutting each other. The separation unit loads into groups is effected on the intermittent conveyor, before transfer of the unit loads to the input roller conveyor. In the known apparatus, after a single row has been formed on the input roller conveyor, the guide lifts the row and displaces it sidewise into the waiting area of the input roller conveyor. Thereafter, the guide returns to its initial position and lifts the next row of unit loads formed on the input roller conveyor and displaces it into the waiting area and so forth, until a complete layer is formed. The complete layer is then shifted by the sliding device sidewise onto two horizontal, movable apart from each other slide plates of the stacker. The layer of unit loads, supported on the two slide parts, upon movement of the plates away from each other is deposited onto a pallet, which is located beneath the two slide plates. Such an apparatus permits one to achieve a substantial output capacity of about a thousand bag-shaped unit loads per hour. However, there is a need to increase this output capacity.
Accordingly, an object of the invention is an apparatus for and a method of palletizing unit loads with a high output capacity.